Many thanks Ian

I was unaware of the hidden 32-bit handles. 'Save As ASCII' did indeed have the effect of resetting my links. I need to ponder the under-the-hood processes at work in this! I expected the designators themselves to be the handles and to use the was/is file to translate.


Ian Wilson wrote:

On 09:45 AM 17/07/2003, Graham Brown said:

Hi all

I want to synchronize my schematics with the reannotated PCB. Reannotation went well - Tools/reannotate etc., but Design/Update Schematics /Preview cannot match any components. Naturally I did a netlist compare and reloaded nets before reannotation just to refresh associations. I've used Protel 99SE/SP6 for several years and am familiar with most operations. It is my sincere hope that I've missed something obvious as this feature could be very useful to us.
Any suggestions please?

Graham Brown

There are two ways of dealing with Sch-PCB synchronization.
1) the Synchronizer - (Update-PCB and Update-Sch)
2) via netlist load and Back Annotate

Mixing the two methods can be fraught with problems unless you keep a very clear head and understand the process and implications. I use the Synchronizer exclusively and have no problems with it. A few others use the netlist load method as they may not have P99SE Sch or they are used to it.

The Synch uses hidden 32-bit numbers (handles) to match components between the Sch and the PCB. These handles are created and matched when the Update-PCB process extracts footprints from libraries. If a component already exists on the PCB that does not have a handles matched with the Sch part the Update-PCB process attempts to match by designator. The use of these hidden handles means that the system can, all being well, maintain matching between component and Sch part through multiple designator changes and re-annotations. "All being well"....I have not seen a situation where the synch has stuffed up without some human assistance (to stuff up).

Using Netlist-Load, Tools-Reannotate, and back annotate to update a sch, requires that only one change re-annotation happen before a back-annotate (otherwise the was-is file gets out of sorts). I think this is correct, I haven't used the process for so long I can't recall the ins and outs.

Mixing the two processes is, in my view, not wise.

How do you manually match (or re-match) PCB components and Sch parts that have lost their handles matching? This is done by designator, by running Update-PCB on the Sch. (Or more specifically, the system offers matches by designator that you can accept or you can manually match up PCB and Sch components - a tiresome task but possibly the best method if the PCB and Sch have wildly different designators.) This will then match the Sch to the PCB by designator.

How can the links get lost or not be there in the first place? Saving-As a PCB as ASCII will break the links - a useful technique when you have to recover from mixing Netlist and Synch. Placing a PCB component manually will not have the link applied and this will have to be established.

So if I was faced with the situation as I think you have explained it, I would start afresh by getting the PCB and Sch designators to match. Saving the PCB as an ASCII version. Reloading the PCB and then running Update-PCB from the Sch. Accept the designator matching (or force the correct matching if you have to). Now the two are re-synched. Then you can annotate on the PCB as you wish and then transfer these designator changes back to the Sch using Update-Sch.

Hope this helps,

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